Transcript Periodicity Period 3 Elements Trends in Physical Properties

Periodicity
Period 3 Elements
Trends in Physical Properties
Atomic Radius
Decreases across period
• No of protons increases across period
• Electrons go into same energy level, level 3
• e- pulled closer to nucleus by extra p+,
• so atomic radius decreases
1st Ionisation Energy
1st Ionisation Energy
General Increase across period
• e- removed from same energy level, level 3
• No of protons increases across period
• Increasing nuclear charge – harder to remove e-
1st Ionisation Energy
e- easier to remove due to
mutual repulsion between 2 ein the same orbital
e- removed from 3p sub
shell further from nucleus
Electronegativity
Increases across period
• No of protons increases across period
• Atomic radius decreases
• Pair of e- in a covalent bond pulled closer to
nucleus by extra p+
Melting Points
Giant Covalent Lattice
Metallic
Bonding
Na 1
Simple molecules
Mg 2
Van der Waals forces
Al 3
delocalised
e- per atom
P4, S8, Cl2
Isolated atoms
V weak Van der
Waals forces
Boiling Points